<template>
  <div class="demo-block" :class="[blockClass]">
    <div class="source">
      <slot name="source"></slot>
    </div>
    <div class="meta" ref="meta">
      <div class="description" v-if="$slots.default">
        <slot></slot>
      </div>
      <div class="highlight">
        <slot name="highlight"></slot>
      </div>
    </div>
    <div class="demo-block-control"
         ref="control" flex="main:center cross:center"
         @click="isExpanded = !isExpanded">
      <i :class="[iconClass]" style="font-size: 18px;"></i>
      <span>{{ controlText }}</span>
    </div>
  </div>
</template>
<script>
  export default {
    data() {
      return {
        isExpanded: false,
        fixedControl: false,
        scrollParent: null
      }
    },
    computed: {
      blockClass() {
        return `demo-${this.$router.currentRoute.path.split('/').pop()}`
      },
      iconClass() {
        return this.isExpanded ? 'ivu-icon ivu-icon-md-arrow-dropup' : 'ivu-icon ivu-icon-md-arrow-dropdown'
      },
      controlText() {
        return this.isExpanded ? '隐藏代码' : '显示代码'
      },
      codeArea() {
        return this.$el.getElementsByClassName('meta')[0]
      },
      codeAreaHeight() {
        if (this.$el.getElementsByClassName('description').length > 0) {
          return this.$el.getElementsByClassName('description')[0].clientHeight +
            this.$el.getElementsByClassName('highlight')[0].clientHeight + 20
        }
        return this.$el.getElementsByClassName('highlight')[0].clientHeight
      }
    },
    watch: {
      isExpanded(val) {
        this.codeArea.style.height = val ? `${this.codeAreaHeight + 1}px` : '0'
      }
    },
    mounted() {
      this.$nextTick(() => {
        let highlight = this.$el.getElementsByClassName('highlight')[0]
        if (this.$el.getElementsByClassName('description').length === 0) {
          highlight.style.width = '100%'
        }
      })
    }
  }
</script>

<style lang="scss">
  .demo-block {
    border: solid 1px #ebebeb;
    border-radius: 2px;
    code {
      font-family: Menlo, Monaco, Consolas, Courier, monospace;
    }
    .source {
      padding: 24px;
    }
    .meta {
      background-color: #fafafa;
      border-top: solid 1px #eaeefb;
      overflow: hidden;
      height: 0;
      transition: height .2s;
    }
    .description {
      padding: 10px;
      box-sizing: border-box;
      border: solid 1px #ebebeb;
      border-radius: 3px;
      font-size: 14px;
      line-height: 22px;
      color: #666;
      word-break: break-word;
      margin: 10px;
      background-color: #fff;
      p {
        margin: 0;
        line-height: 26px;
      }
      code {
        color: #5e6d82;
        background-color: #e6effb;
        margin: 0 4px;
        display: inline-block;
        padding: 1px 5px;
        font-size: 12px;
        border-radius: 3px;
        height: 18px;
        line-height: 18px;
      }
    }
    .highlight {
      pre {
        margin: 0;
      }
      code {
        &.hljs {
          margin: 0;
          border: none;
          max-height: none;
          border-radius: 0;
          &::before {
            content: none;
          }
        }
      }
    }
    .demo-block-control {
      border-top: solid 1px #eaeefb;
      height: 44px;
      box-sizing: border-box;
      background-color: #fff;
      border-bottom-left-radius: 4px;
      border-bottom-right-radius: 4px;
      text-align: center;
      margin-top: -1px;
      color: #d3dce6;
      cursor: pointer;
      i {
        font-size: 16px;
        line-height: 44px;
        transition: .3s;
      }
      > span {
        font-size: 14px;
        line-height: 44px;
        transition: .3s;
      }
      &:hover {
        color: #409EFF;
        background-color: #f9fafc;
      }
      & .text-slide-enter,
      & .text-slide-leave-active {
        opacity: 0;
        transform: translateX(10px);
      }
    }
  }
</style>
